More than 1,400 earthquakes were recorded in Oklahoma in 2011, by far the most in state history, including a 5.6 magnitude earthquake, the largest in the state since 1952.
“The spike is very real,” said Austin Holland, seismologist at the Oklahoma Geological Survey.
“We have had about a 100 fold increase in the number of earthquakes each year and it’s not just because of additional instrumentation or anything like that, it’s a real change in the rate of earthquakes,” Holland added.
Earthquakes occur due to breaking or movement of tectonic plates deep beneath the earth’s surface.
Recently, scientists have begun to link the controversial process of hydraulic fracturing or “fracking” done by oil and gas companies to the increase in earthquakes. Fracturing has been around since the 1940s, as companies drill deep into the earth spewing a mixture of water and sand into shale rock, allowing the ingestion of natural gas. This method is practiced around the world but it is also banned in several countries, most notably France.
A recent article by Karen Keranen published in the geoscience journal Geology, suggests that there is more evidence connecting drilling to the rise in Oklahoma earthquakes.
“I do not think there is any good evidence which can link fracturing to earthquakes” said Dr. Chandra Rai, director of the Mewbourne School of Petroleum and Geological Engineering at the University of Oklahoma.
He believes that more research needs to be done before conclusions are drawn and before companies need to re-evaluate their drilling techniques.
“In the state of Oklahoma hydraulic fracturing is not new; thousands and thousands of wells have been fractured. This process is very old,” he added.
Seismologists including Austin Holland are not entirely convinced that oil and gas companies are culprits in the rise in Oklahoma earthquakes. He believes that it is a natural process and that drilling may only be accelerating the process.
“Drilling itself probably does not have anything to do with it. Oklahoma is being squeezed east to west and it’s an old plate tectonic boundary so we have a lot of old existing faults,” Holland said.
While the debate continues, Holland says that no matter the cause, Oklahomans should expect to be shaken a little more for the next several years.
“There is a noticeable change in the amount of earthquakes in the central United States at least. I see no reason that we’re going to like all of the sudden stop having earthquakes. I would expect perhaps people feeling more earthquakes,” he said.
For further information about earthquakes or what to do during an earthquake visit http://www.okgeosurvey1.gov/.
